how much of what we believe about gradient actually comes from purity threads
Genuine question, and the title is the question: how much of what we believe about gradient actually comes from purity threads. UV response is not uniform across species. At 214nm you are looking at the peptide bond, which is why it is the working wavelength for this class; at 280nm you only see tryptophan, tyrosine…
Carryover from a previous high-concentration injection looks exactly like a small impurity. The blank injection is four minutes and it removes the ambiguity entirely.
How old is the column and roughly how many injections has it seen?
Is that baseline drawn by the software or by hand?
a shoulder is not an impurity until you can resolve it
system suitability before you believe any number on the run
you cannot report to two decimals off that baseline
you cannot report to two decimals off that baseline
This is the whole methodological point of the board in one line.
Small fix — 214nm, not 210. It matters for the comparison you are making with the other run.
This. A shoulder that does not baseline-resolve is a question, not a quantity.
That is area percent, not mass percent. The trace cannot give you the second one.
reproducibility beats resolution if you only get one of them
report the method or do not report the number